American commanders are trying to determine how large a force is needed to create a secure environment for the people of Iraq, Defense Secretary Donald H. Rumsfeld (search) said Thursday. He denied reports that U.S. forces had orders to shoot looters.

"That was hyperbole," Rumsfeld said. The rules of engagement for troops in Iraq (search) have not changed, he said.

Rumsfeld said that the rules all long have authorized whatever use of force was necessary "for self-defense and other selective purposes."

U.S. commanders began a new program to get more troops into Iraqi neighborhoods to help with garbage pickup, health care and other services, said Maj. Gen. Buford Blount, commander of the U. S. Army's 3rd Infantry Division (search).

The intent, Rumsfeld said, is to create a physical presence so that civilians can see U.S. forces are "determined to see that the environment becomes permissive for the people of Iraq."

Turning to Saudi Arabia (search), Rumsfeld said that Monday's bombing attacks in Riyadh would not thwart U.S. plans to scale back the military presence in the kingdom. And he said the intended reduction in force is not out of the ordinary.

"Force protection levels change in country to country all over the world all the time," the secretary said, adding that he was "comfortable" that the remaining U.S. forces would be adequately protected from terrorist attacks.

Rumsfeld said he anticipates terrorists would try more attacks in the future, but Al Qaeda's overall ability to carry them out has been severely hobbled by the pressure being applied to its network.

"It's more difficult to recruit. It's more difficult to retain. And that's a good thing," Rumsfeld said.

Adding to the difficulties are continuing questions about terrorist leader Usama bin Laden, Rumsfeld said.

The secretary said he doesn't know whether bin Laden is alive or dead, but there are still some countries willing to provide safe haven to Al Qaeda operatives.

"There are still countries that are harboring terrorists. We know there are senior Al Qaeda in Iran," Rumsfeld said.

Speaking to Pentagon reporters in a videoconference from Baghdad, Blount said commanders are putting more and more American soldiers on the streets. Units with some 230 Humvees are flowing into the area Thursday and Friday and other troops also are on their way from staging areas in Kuwait, he said.

After they are in place, commanders will reassess to see when they can send home troops of the 3rd Infantry Division, he said.

"A lot of my forces have been over here since September and fought a great fight and are doing great work here in the city," he said. "But if you asked the soldiers, they're ready to go home."

Rumsfeld said Wednesday that security is "the one thing that's central to success" and the United States has a plan to provide it. But he said the 142,000 U.S. troops inside Iraq, plus more than 15,000 additional troops to arrive soon, could not restore order instantly.

There are 49,000 U.S. troops in and around Baghdad, and they plan to make sure those disrupting the city "are stopped and either captured or killed," Rumsfeld said.

Blount said a program called Task Force Neighborhoods began Thursday and will send medical teams to help Iraqis with minor injuries or give vaccinations. The program will also send engineers with dump trucks and a paymaster to hire Iraqis to do repairs and help with pickup of garbage, which he said hadn't been collected in some areas in a couple of months.

Blount said officials have "high expectations" for the program, which will make troops more visible to the Iraqis as well as give Iraqis a sense of pride and responsibility in efforts to get the country going again after the fall of Saddam Hussein's regime.

Also on Thursday, U.S. forces wounded a looter from a group they said fired on Americans.

Looters fired on 101st Airborne Assault Division soldiers Thursday morning in Mosul, said the U.S. Central Command. Soldiers returned fire on the looters, wounding one, and four others escaped, it said.

No U.S. casualties were reported, but the incident "highlights the dangerous nature" of the security job in Iraq weeks after the major combat ended, the statement said.

Under pressure to impose order on a still-lawless capital, U.S. military commanders Wednesday defended their approach to keeping Baghdad safe and said they were aggressively targeting looters. They denied a published report that they had authorized a shoot-on-sight policy.

Blount said a total of 600 were currently detained at a holding facility at Baghdad International Airport. Those who committed a crime with the aid of a weapon would be detained until Iraq's judicial authorities are fully operational again and are able to take charge of them, he said.